Filtering medium.



J. E. PORTER.

FILTERING MEDIUM.

APPLICATION IILED MAY 0,1913.

1,11?,601. Patented Nov. 17, 1914.

' sity having a uniform or JAMES EDWARD PORTER, OF SYRACUSE, N

D STATES PATENT orrron.

. EW YORK, ASSIG-NOR TO GENERAL FILTRA- TION COMPANY, me, or nocHEs ER,NEW YQBK, A CORPORATION OF NEW YORK.

rrmnnane mnnium.

Speelflcation of Letters Patent.

Patented Nov. 17, 1914.

Application filed May 9, 1913. Serial No. 766,522.

To all whom it may concern Be it known that I, JAMES EDWARD Pon- TER, ofSyracuse, in the county of Onondaga, in the State of New York, haveinvented new and useful Improvements in Filtering Mediums, of which thefollowing, taken in connection with the accompanying drawings, is afull, clear, and exact descrip-- The main object isto produce at acomparatively low cost a highly coherent mineral body ofany desiredform, size or den graded de ee of porosity and practically indestructlle by acids, alkalies and other liquids as well as by gases or Vaporsunder widely varylng degrees of heat and cold. In other words, I havesought to advance the art of making porous products by thoroughly mixingcertain mineral constituents in a more or less finely comminuted stateaccording tothe degree of porosity desired and by fusmgthe comminutedparticles of one of the COIlStltlL cuts of the mixture so as to estabhsha firm and tenacious bond between such particles and at the same timeassuring a umform degree of porosity throughout the entire bod A furtherobject is to producesuch a porous product in which the. expans1on ofmass is-counteracted to retain the articles in the same shape as moldedor compressed.-

Another object is tobe'able to produce a rapid, filtering body of greatstrength ;and little resistance-g by superimposing n-"the course ofmanufacture, a thin layer of dense but highly porous material upon athick layer of muchhcoarser but highly porous r c r 4:" mu" Otherobjects and-uses willbe brought'out in the iOllOWillgfdGsCliPtlOn. 1 l'the mang e 1.:harashewm d ma of a porous dy constructed 1n accord nce wth y n a twnansls ewms aseme to the use to which it Th be evident fromthe following descrip of layers or strata of different degrees ofporosity, gradually increasing in density from bottom to top. Thematerial employed in the manufacture of this porous mineral productpreferably consists of ground or crushed quartz, sand, or similar silicacontaming substances which may be comminuted to any desired degree andaccording to the degree of porosity required, the comminuted. particlesbein thoroughly mixed with a quantity of poW ered glass and then boundtogether.by the fusion of the lass. is glass may be added as such in aely powdered or granular form orin the form of its constituents.whichbecome glass at the proper temperature.

The sand and quartz or similar silica containing substances may be mixeddry with or granular glass or its the finely powdered constituent in'varying proportions according to the nature of the article which it mayhe *desired to manufacture, thethinner bodies or articles requiring moreof the flux or fusible constituent as glass than the thicker bodies orarticles in order to give such thinner bodies the desired strength. Thedry mixture may be contained in suitable molds and heated therein abovethe fusing point of the lass or the dry mixture may be further IHJXGd'with sufiicient water and, if necessary some adhesive substance oforganic origin such as dextrin, gum arabio or the like so that thearticles canbe molded by pressure and then removed from the moldingpress and placed in suitable molds. or saggers for burning. This.material made according to my process may be-heated very much above thefusing oint of the glass without detriment. In factvWiththe'comparativclys'mall amount of binder, (glass). which I,uselthe.mixture maybe heated-to, 2800 F. orhigher with the most beneficialresults. 'In this i. tterrcase, lalgglut 1()% ,of 7 water and 1% or essof the a eSIVQhmitiiter are ordinarily sufiiqient, the adhesiae'beingflniven fi es roye 3 1 1 bu ing and is.only"used'toinakethe'v masscoherent w :elhan p lwi'; ":HZ 1mins certain -shaped, articles by eitherthe,dry,gr wet inixturelmethod a suitable percentageof a selected gradeof'inearth also known as kieselguhr or dilingfdurihg'the course 'ofmanu- I.

' and 20'% of finely powdered glass may be.

about 1155 C. (211l F.).

tion to counteract the expansion of the mass in fusion, thus enablingthe finished article to be readilyremovedfrom the molds inthe sizeorshape desired.

As an example of anideal product, 80% of clean white quartz sand ofsuitable mesh employed, these constituents being mixed thoroughly,molded either dry or wet andthen fired above the fusing point of theglass. If ground common window-glass is used, the mixture should beheated up to The difierent lots of ground glass used may, of course,yary in their fusing points butan observant attendant can distinguishwhen this point is reached. The fusing point is not, therefore,

confined to any specific temperature noris the invention limited to theabove pro ortioned' mixture for the reasons given an for the furtherreason that a variation :in the roportion of the constituents is requireto produce the desired porosity, that is coarse or fine pores. It isevident, however, that variation in the proportions of the sand andglass as well as variation in the mesh of the sand itself may benecessary to control these latter factors. As an example of a productmade from glass-forming constituents the following may be given: n 75parts of clean, white, quartzand, of suitable mesh and 25 parts of thefollowing mixture this mixture then mixed with the 75 parts of sand.'This' formula as a whole is for a porous com osi'tion consisting ofabout 7 5% To make this sand and'a out 25% glass.

parts of glass approximately 18 parts of. silica,

fi parts of carbonate of soda and 5.75

ents. react chemically, under'the. influence ,of

' heat,:to form glass. W'ithrhemically pure carbonate of limel andcarbonate of spda, 5.02 parts of carbondioxid would be given ofi. undertheoretical conditions from the above specified amounts ofjlime'andsoda, thus producing but 24.73fparts of glassinstead of 25 parts.But-none of the materials employed would be chemically pure andtheoretical conditions a1- not always obtainable consequently allowancewas made in the formula given for commercial. salts and practicalconditions. -'I The follo of. carbonate of lime are required. The

tumour equations and calculations should make the matter clear:

Na,oo,+heat=Na,o+oo, 1.06:44:=6:2.49

CaCO,'-i-heat=a0+(l0,' 100:44::5.75:2.53

2.49 parts of C0, are produced from 6 parts carbonate of soda, 2.53parts-of C0, are produced from 5.75 parts carbonate of lime. 5.02 partsof CO (total) are therefore produced from both of these ingredients, andgiven ofi as a gas during the heating. The sodium oxidiNa O) andcalcium.

oxid (CaO) of course combine with the silica to form glass, and saidglass simultaneously with its formation, binds the 7 5 parts of sandtogether to produce the'porous product. In this latter method ofmanufacture, the reaction between the glass-forming constituentscommences about 1040 C.

(1904: F.) and apparently .ends' about- 1200 C. (2192 F.) and thetemperature should be maintained near this latter point for a few hoursto insure the complete formation of the glass and the elimination of thedecomposition products of the reaction v(00;). While this latter methodrequires -more time and attention than. the former,-

it produces products practically identical when properly carried out,and may be used in case supplies of waste glass are not available. Thisporous mineral product may also. be made up in layers of varyingporosity. For example, a plate say two inches thick over all, may haveone and one-halfinches of coarse sand as a base, and one-half inch of avery fine sand for the remainder. Each grade of sand being mixedseparately with the binding agent and placed in layers in the mold, sothat upon fusion a single plate,

coarse grained on .one side and fine grained on the other is obtained.For some filtration operationsv a very fine pored plate may be requiredand as the resistance of the plate,

as a whole is decreased by having but onehalf inch instead of two inchesof fine media for the liquid to pass through, this feature is ofimportance. =A't' the: same'time a two inch plate may be required tosustain the weight or pressure'put upon it.

Composite plates'or productahaving for even incorporated top, bottom, orthrough out, as may be desired. vExtra large plates or shapes may alsobe reinforced by embedding in the mixture during the molding,

metal rods or other suitable reinforcing material.

The porouseral product is as 'acidv or as a means for finely proof aseither of its constituents (silica-I- glass) which is racticallabsolute, and as a rapid filter me ium for ot strong acids is especiallyadapted. As is well known, hot strong alkalies attack silica and glassto some extent, but the material is nevertheless extremely servicablefor all ordinary uses in this line.

As a ralpiid filtering medium for neutral, acid, or a aline liquids orsolutions, either hot or cold, and for the filtration or purification ofair, gases, fumes or vapors, the above described porous mineral productis practically indestructible. As a means of agitating and aeratingliquids or emulsions, asin the cyanid process of extracting ores, thisporous product when installed as a false bottom in tanks, isparticularly eflicient. It may be also used as. a container formoisture, as in humidors, and for other liquids as acetone in gascylinders, and also as a medium suitable for impregnation with catalyticsubstances used in manufacturing processes dividing gases or liquids inthe manufacture of chemicals, as for example, the saturation ofammoniacal brine liquors with CO, in the manufacture of soda, or thesaturation of water with S0,, in the manufacture of sulfuric acid. Inother operations requiring a heat, acid, and alkali resisting materialof a porous nature, this material 15 admirably adapted. Owmg to itsnumerous air cells, it is also an efiicient heat and cold insulatingmaterial and solelyof from 75% to 85% of silica-containing substance,and from 25% to 15% of powdered glass mixed therewith and fused 1n themixture. V

In witness whereof I have hereunto set my hand this seventh day of May1913.

JAMES EDWARD PORTER. Witnesses:

H. E. CHASE, E. A. THOMPSON.

